Dome Runner Ring

[ribuck]

Hi all,

I'm looking to see if anyone knows someone who can fabricate some kind of steel runner ring for a dome.

I made my home made dome and initially just fashioned a 6ft wide runner ring out of pvc cladding material, as a temporary measure.

Basically I have a square wodden shed type base, and sitting in top of this is a rotating dome approx 6.5ft wide.

I'm happy for any suggestion or ideas for a new running gear setup

Rich.

[ollypenrice]

Hi,

Fabricators will make them for you. They usually supply them with a sort of 4-spoke cross welded in to keep them circular till fitted, then you angle grind the 'spokes' out once in situ. Or so I believe.

Olly

[Macmarch]

Hi there,

I can recommend JMR Section benders Ltd 0208 593 7324

They are experts in rolling and bending all kinds of sections. They even designed the machines to do the rolling. I used to work with them back in the 60's and I will be getting them to roll my dome rings later this year.

cheers

Ray

[George]

Think Centroid had one fabricated a while back, no doubt he will comment on this soon

[ribuck]

Does anyone have any good ideas for ring and runner wheel setup's ?

[barkis]

I built my own dome many years ago. I was fortunate enough to get a local engineering firm to roll me a ring of 4" wide 1/4" steel into a 10foot diameter. It had to be made from two lengths of metal though, but the weld was superb, and hardly noticable.

I had 4 6x4 inch plates welded mid section on the ring, at 90 degree intervals. These enabled me to bolt the ring to the four walls of the building on L brackets I also had the superstructure for the dome itself fabricated. The work cost me a total of £125.

I skinned it myself, using galvanized sheeting, from which I cut the petals and riveted to the framework, a long and tedious job, but it brought a great deal of satisfaction.

I used commercial size Alternator pulleys for the wheels of the dome. I machined out the centres to take roller bearings. I only made four, as I would have had difficulty keeping more in contact with the ring. Anyway, as it turned out, I could rotate the dome very easily by hand. The pulley wheels, which were made of cast iron sat nicely on the track, and had a good depth. I kept the dome secure by bolting four u shaped keepers ahead of each bearing, so the dome could never jump off the track. The dome viewing aperture was simply aluminium sheet I bought second hand. I folded and pressed the edges over, and fed it into some aluminium window moulding, riveted either side of the slit. To gain access to the zenith of course, it was necessary to keep the slide short, and slide it completely over the hemisphere. When slid closed, the hole left, was filled by a hinged door of aluminium, which lowered down on a chain, so I had access to the horizon too. When there was no buildings in the way that is.

My 12" reflector, which was also completely home made. (Not boasting here believe me) resided in that dome for many years.

That observatory brought me great happiness, and some wonderful times. A load of people saw the heavens for their first time in that place, and they all went away with happy faces. Now I am just about to complete my double sided sliding roof obsy, Its taking time because I'm a bit old to be doing it flat out, I am still enjoying it though, and still have that eager anticipation I had with the first one I built.

Don't get discouraged in any way, you will get there, and you will have a great place to perform your astronomy.

Good Luck with it.

Ron.

[ribuck]

Hi Ron,

I already love my Obs, it's great that i can use it even on Windy nights or use my setup with no dewwing on all my equiptment.

I've just reached the point, where the dome is starting to stick a little bit, so it's now time to do the ring properly.

I also want to redesign the dome so i can get to the zennith (think that's the right term) as i'm limited to about 60 degree's which means limited exposure time, hence wanting to make a better opening to view through.

P.s. Any diagrams people have would be great.

Rich.

[Macmarch]

Have a look at this obsy. For those who have not yet built the dome, this one has no curves.

Observatory

[barkis]

Sorry Rich, I should have remembered you already had your obs.

most of what I wrote was unnecessary. Must be senility setting in.

Ron.